Repairing a Meyer Görlitz Helioplan 40mm f/4.5 Lens

This Meyer Görlitz Helioplan 40mm f/4.5 lens was manufactured around 1949/50. It was the widest lens for SLR cameras, before retrofocus designs were developed.

 

One thing that is special about many of these old lenses is the larger number of aperture blades. This one has twelve, resulting in beautiful circles for out-of-focus shapes.

This piece has the Exakta mount.

For a 75 years old lens, this one is, cosmetically, in pretty good shape. But, as expected, its aperture is oily and the focus is extremely stiff. But these are easy to fix. 

Maybe, at a later date, I will add more text. But the pictures and their annotations make it pretty clear, how to disassemble this lens. As usual: When disassembling the helicoids, pay good attention when they separate, so you can insert them exactly like they were before. Otherwise, you may loose infinity focus.

Removing the rear glass.

And removing the front glass.

This gives access to the aperture blades which can be cleaned in-place from both sides, using isopropyl alcohol or lighter fluid.

With the focus set to infinity, the focus ring is removed. 

These two screws guide the helicoids (helicoid keys),

While removing the two screws, don't rotate the front piece. Then, carefully remove the front piece, and: remember its initial position, count how many turns it took to become free, and (most important!) remember exactly its position when it becomes free. That's where it has to be inserted later.

75 year old grease!
Then, the second helicoid is removed (I did not take a picture of that step).

These are all the pieces - cleaned!!

Now: Putting everything back together, starting with the helicoids (after placing a small amount of helicoid grease on them).

The first helicoid is back....

... and the second one too. Now the helicoid keys are inserted.

Last step: Cleaning the glass elements before inserting them.

It's as good as new!

A few test shots show that it has a very soft rendering. I am not sure if this is caused by a small amount of fog (it's hard to tell looking through the lens since the glass elements are so small) or if it's typical for this lens. In any case, it makes this lens very special.

More of my lens repair tutorials can be found here.